1. Field of the Invention
The present invention relates to a propylene/ethylene-xcex1-olefin block copolymer which is superior in impact resistance and processability. In the present invention, the propylene/ethylene-xcex1-olefin block copolymer means a polymer obtained by successively synthesizing a propylene polymer component and an ethylene-xcex1-olefin copolymer component. However, this block copolymer is not a true block copolymer with which said components (moieties) are perfectly chemically bonded each other, but is a kind of polymer compositions.
2. Description of the Related Arts
Polypropylene has widely been used for various purposes because of excellent physical properties. For example, polypropylene has recently been used for various purposes such as automobile interior/exterior parts, electrical parts, etc. because of excellent rigidity, heat resistance, gloss and moldability as well as low price. However, there was a problem that polypropylene is insufficient in impact resistance because of the crystallizability and, therefore, the use thereof is limited.
In order to improve the impact resistance of propylene, a process of polymerizing propylene with ethylene or the other olefin stepwise to form a block copolymer has hitherto been used. In the production of a block copolymer of conventional stereoregular polypropylene, a titanium trichloride catalyst or a titanium-magnesium composite catalyst is exclusively used. These catalysts normally have low randomness in the copolymerization reaction and wide composition distribution. Therefore, even if a rubber-like copolymer is produced at the second-stage after crystalline polypropylene was produced at the first-stage, the impact resistance is sometimes insufficient in a specific use.
As a method of improving the non-homogeneity of the rubber-like copolymer moiety, there is disclosed a method of producing a propylene/ethylene-propylene block copolymer or a block copolymer of propylene/propylene and at least one of ethylene and an xcex1-olefin having 4 to 20 carbon atoms, using an uniform catalyst such as metallocene, which produces a homogeneous copolymer having large randomness (Japanese Patent Kokai Nos. 5-202152 and 6-172414). However, when using the above copolymer as the rubber-like copolymer moiety, the impact resistance is improved but the rigidity as an intrinsic characteristic of polypropylene is liable to be drastically deteriorated.
On the other hand, as a method of maintaining the rigidity to high level with improving the impact resistance of polypropylene, there has been used a method of blending polypropylene with a rubber-like substance having large randomness and narrow composition distribution, such as ethylene-propylene copolymer rubber (EPR), ethylene-butene copolymer rubber (EBR), ethylene-propylene-diene copolymer rubber (EPDM), etc. Although these rubber-like substances are normally produced with a vanadium catalyst system, there has recently been disclosed an improvement accomplished by blending an ethylene-higher xcex1-olefin copolymer rubber (xcex1-olefin having 4 to 8 carbon atoms) with an uniform catalyst system such as metallocene catalyst system (Japanese Patent Kokai Nos. 6-192500, 6-192506, 6-248156 and 7-102126). However, there arises a problem in blending operation that such a rubber-like copolymer can not be used after pelletizing, like a crystalline resin, because the shape thereof is not easily handled according to the composition. Besides, with respect to a method of blending such a rubber-like copolymer, an operation of blending is required and a kinds of the rubber-like copolymers is expensive.
There is also disclosed a technique about a thermoplastic elastomer which is superior in moldability by means of olefin block copolymerization (Japanese Patent Kokai (laid-open) Nos. 57-61012, 58-32616, 58-71910, 58-103548, 59-105008 and 1-297408). In the production of these olefin block copolymers, a titanium trichloride catalyst system or a titanium-magnesium composite catalyst system is mainly used. However, the mechanical properties such as impact resistance is sometimes insufficient in a specific use. Furthermore, when using the catalyst, relative reactivity of xcex1-olefin to ethylene tends to be markedly lowered depending upon the increase of the number of carbon atoms of the xcex1-olefin in view of the property of the catalyst.
An object of the present invention is to provide an olefin block copolymer which is superior in impact resistance and rigidity without blending a rubber-like copolymer having excellent randomness and narrow composition distribution, and a process for producing the same.
Another object of the present invention is to provide an olefin block copolymer which is superior in balance between the impact resistance and rigidity.
Still another object of the present invention is to provide an olefin block copolymer which is superior in heat resistance, impact resistance and processability, and has a noticeable effect for improving physical properties of polypropylene when adding it to polypropylene.
The present inventors have intensively studied so as to accomplish the above objects. As a result, the present invention has been completed.
According to the present invention, there is provided a propylene/ethylene-xcex1-olefin block copolymer obtained by polymerizing propylene to form a polypropylene component in a first-stage and copolymerizing an ethylene and xcex1-olefin having 4 to 18 carbon atoms to form a random copolymer component in a second-stage, which satisfies the following conditions (I) to (III):
(I) a content of the polypropylene component(1) having an intrinsic viscosity ([xcex7]) measured in tetralin at 135xc2x0 C. of from 0.5 to 5.0 dl/g is from 5 to 95% by weight;
(II) a content of an xcex1-olefin in the random copolymer component(2) is from 5 to 40 mol %, and a content of the ethylene-xcex1-olefin random copolymer component having a xcfx81 value represented by the following general formula:
xcfx81=2[E]xc2x7[A]/[EA]
(wherein [E] represents a molar fraction of ethylene, [A] represents a molar fraction of the xcex1-olefin and [EA] represents a molar fraction of a dyad chain of ethylene and the xcex1-olefin) within the range from 0.5 to 1.5 is from 5 to 95% by weight; and
(III) an intrinsic viscosity ([xcex7]) of the propylene/ethylene-xcex1-olefin block copolymer measured in tetralin at 135xc2x0 C. is from 0.5 to 5.0 dl/g.
The present invention also provides a propylene/ethylene-xcex1-olefin block copolymer wherein the content of the component (1) is from 50 to 95% by weight and the amount of the component (2) is from 5 to 50% by weight.
Furthermore, the present invention also provide a propylene/ethylene-xcex1-olefin block copolymer wherein the content of the component (1) is not less than 5% by weight and less than 50% by weight and the amount of the component (2) is more than 50% by weight and not more than 95% by weight.
Furthermore, the present invention provide a process for producing the above-described copolymers and a molded article therefrom.
The present invention will be explained in detail below.
The propylene/ethylene-xcex1-olefin block copolymer of the present invention is composed of the polypropylene component and the ethylene-xcex1-olefin random copolymer component and obtained by producing a polypropylene component in the first-stage of polymerization and an ethylene-xcex1-olefin random copolymer component in the second-stage of the polymerization. The xcex1-olefin used in the present invention is an xcex1-olefin having 4 to 18 carbon atoms, preferably 4 to 8 carbon atoms. Particularly, 1-butene, 1-hexene and 1-octene are preferably used. The content of the polypropylene component in the propylene/ethylene-xcex1-olefin block copolymer is within the range from 5 to 95% by weight, and the content of the ethylene-xcex1-olefin random copolymer component is within the range from 5 to 95% by weight. Each content may be changed within the wide range. However, when the content of polypropylene component is less than 5% by weight, the processability is deteriorated. On the other hand, when it exceeds 95% by weight, the effect of improving the impact resistance becomes poor.
A preferred range of the proportion of the polypropylene component to the ethylene-xcex1-olefin copolymer in the propylene/ethylene-xcex1-olefin block copolymer of the present invention can be selected from the above range according to the desired purpose. When using for the purpose to which the impact resistance is required, in addition to the processability, the content of the polypropylene component in the propylene/ethylene-xcex1-olefin block copolymer is preferably not less than 5% by weight and less than 50% by weight, and the content of the ethylene-xcex1-olefin random copolymer is preferably more than 50% by weight and not more than 95% by weight. In this case, the impact resistance is further enhanced by increasing the content of the ethylene-xcex1-olefin random copolymer component in the propylene/ethylene-xcex1-olefin block copolymer to more than 50% by weight.
In the use to which physical properties superior in balance between the impact resistance and rigidity are required, the content of the polypropylene component in the propylene/ethylene-xcex1-olefin block copolymer is preferably from 50 to 95% by weight, and the content of the ethylene-xcex1-olefin random copolymer component is preferably within the range from 5 to 50% by weight. There can be obtained those having physical properties, which is superior in balance between the impact resistance and rigidity, by increasing the content of the polypropylene component to 50% by weight or more.
The content of the xcex1-olefin in the ethylene-xcex1-olefin random copolymer component is from 5 to 40 mol %. When the content of the xcex1-olefin is less than 5 mol %, the effect of improving the impact resistance becomes poor. On the other hand, when it exceeds 40 mol %, the processability is deteriorated. Particularly, when the content of the polypropylene component is not less than 50% by weight, the rigidity unfavorably decreases in addition to deterioration of the processability.
When the polypropylene component of the propylene/ethylene-xcex1-olefin block copolymer of the present invention is produced, a small amount of ethylene or the xcex1-olefin (preferably not more than 10 mol %) other than propylene can be copolymerized as far as the object of the present invention is not adversely affected. When the ethylene-xcex1-olefin random copolymer component is produced, a small amount of propylene or the other xcex1-olefin (preferably not more than 3% by weight) can be copolymerized as far as the object of the present invention is not adversely affected.
The ethylene-xcex1-olefin random copolymer component in the present invention has a xcfx81 value represented by the following general formula:
xcfx81=2[E]xc2x7[A]/[EA]
(wherein [E] represents a molar fraction of ethylene, [A] represents a molar fraction of xcex1-olefin and [EA] represents a molar fraction of a dyad chain of ethylene and an xcex1-olefin) within the range from 0.5 to 1.5.
In the ethylene-xcex1-olefin random copolymer component of the present invention, this xcfx81 value is an index which represents a distribution state of each monomer constituting a random copolymer chain. When the xcfx81 value is closer to 1, little blocked chain is formed and the resulting copolymer is a copolymer having large randomness and narrow composition distribution. That is, the larger the randomness of the ethylene-xcex1-olefin random copolymer, the larger the effect of improving the impact resistance of polypropylene.
The polypropylene component in the propylene/ethylene-xcex1-olefin block copolymer of the present invention, has an intrinsic viscosity ([xcex7]) measured in tetralin at 135xc2x0 C. of from 0.5 to 5.0 dl/g, preferably from 0.5 to 3.0 dl/g, more preferably from 0.8 to 2.0 dl/g, and the intrinsic viscosity can optionally be changed within the above range according to the desired purpose.
The ethylene-xcex1-olefin random copolymer in the propylene/ethylene-xcex1-olefin block copolymer of the present invention has an intrinsic viscosity ([xcex7]) measured in tetralin at 135xc2x0 C. of from 0.5 to 5.0 dl/g. When the content of the polypropylene component is within the range from 50 to 95% by weight, the intrinsic viscosity is preferably from 0.5 to 3.0 dl/g. When the content of the polypropylene component is not less than 5% by weight and less than 50% by weight, the intrinsic viscosity is preferably from 1.0 to 3.0 dl/g. Further, the intrinsic viscosity can optionally be changed within the above range according to the desired purpose. However, when [xcex7] is less than 0.5 dl/g, the stickiness sometimes appear. On the other hand, when it exceeds 5.0 dl/g, the flowability becomes poor. In both cases, the moldability is unfavorably deteriorated.
The propylene/ethylene-xcex1-olefin block copolymer of the present invention can be produced by using a homogenous transition metal complex catalyst, that is, a catalyst containing a combination of (A) a compound of transition metal of Group IV of the Periodic Table, having a cyclopentadienyl ring and (B) at least one selected from the group consisting of (i) aluminoxanes, (ii) compounds which reacts with the transition metal compound to form an stable anion and (iii) organoaluminum compounds, as essential components.
As the transition metal compound having a cyclopentadienyl ring, there can be preferably used a compound wherein a cycloalkadienyl group or a substituted group thereof is coordinated on the metal. Specifically, there can be used a zirconium or hafnium compound containing, as a ligand, a multi-coordination compound wherein at least two groups selected from the group consisting of indenyl group, substituted indenyl group and a partially hydrogenated group thereof are bonded through a lower alkylene group.
Examples of the transition metal compound (A) include stereorigid chiral compounds of zirconium and hafnium, such as ethylenebis(indenyl)zirconium dichloride described in H. H. Brinzinger et al., J. Organometal. Chem., 288, 63 (1985), ethylenebis(indenyl)hafnium dichloride described in J. Am. Chem. Soc., 109, 6544 (1987), dimethylsilylenebis(methylcyclopentadienyl)zirconium dichloride described in H. Yamazaki et al., Chemistry Letters, 1853(1989), dimethylsilylenebis(1-indenyl)zirconium dichloride described in W. Spaleck et al., Angew. Chem. Int. Ed. Engl., 31, 1347 (1992) and the like.
Specific examples thereof include ethylenebis(1-indenyl)zirconium dichloride, ethylenebis(4,5,6,7-tetrahydro-1-indenyl)zirconium dichloride, ethylenebis(2methyl-1-indenyl)zirconium dichloride, ethylenebis(3-methyl-1-indenyl)zirconium dichloride, ethylenebis(4-methyl-1-indenyl)zirconium dichloride, ethylenebis(5-methyl-1-indenyl)zirconium dichloride, ethylenebis(6-methyl-1-indenyl)zirconium dichloride, ethylenebis(7-methyl-1-indenyl)zirconium dichloride, ethylenebis(2,3-dimethyl-1-indenyl)zirconium dichloride, ethylenebis(4,7-dimethyl-1-indenyl)zirconium dichloride, ethylenebis(2,4,7-trimethyl-1-indenyl)zirconium dichloride, dimethysilylbis(methylcyclopentadienyl)zirconium dichloride, dimethysilylbis(tbutylcyclopentadienyl)zirconium dichloride, dimethysilylbis(dimethylcyclopentadienyl)zirconium dichloride, dimethysilylbis(trimethylcyclopentadienyl)zirconium dichloride, dimethysilyl(methylcyclopentadienyl)(dimethylcyclopentadienyl)zirconium dichloride, dimethysilylbis(methylcyclopentadienyl)(t-butylcyclopentadienyl)zirconium dichloride, dimethysilylbis(1-indenyl)zirconium dichloride, dimethysilylbis(4,5,6,7-tetarhydroindenyl)zirconium dichloride, dimethysilylbis(2-methyl-1-indenyl)zirconium dichloride, dimethysilylbis(3-methyl-1-indenyl)zirconium dichloride, dimethysilylbis(4-methyl-1-indenyl)zirconium dichloride, dimethysilylbis(5-methyl-1-indenyl)zirconium dichloride, dimethysilylbis(6-methyl-1-indenyl)zirconium dichloride, dimethysilylbis(7-methyl-1-indenyl)zirconium dichloride, dimethysilylbis(2,3-dimethyl-1-indenyl)zirconium dichloride, dimethysilylbis(4,7-dimethyl-1indenyl)zirconium dichloride, dimethysilylbis(2,4,7-trimethyl-1-indenyl)zirconium dichloride, dimethysilylbis(2-methyl-4-isopropyl-1indenyl)zirconium dichloride, dimethysilylbis(4,5-benz-1-indenyl)zirconium dichloride, dimethysilylbis(2-methyl-4,5-benz-1-indenyl)zirconium dichloride, dimethysilylbis(4-phenyl-1-indenyl)zirconium dichloride, dimethysilylbis(2-methyl-5-phenyl-1-indenyl)zirconium dichloride, dimethysilylbis(2-methyl-4-phenyl-1indenyl)zirconium dichloride, dimethysilylbis(2-methyl-4naphthyl-1-indenyl)zirconium dichloride, isopropyl(3-tbutyl-cyclopentadienyl)(3-t-butyl-indenyl)zirconium dichloride, isopropyl(3-t-butyl-cyclopentadienyl)(3-methyl-indenyl)zirconium dichloride, ethylenebis(1-indenyl)hafnium dichloride, ethylenebis(4,5,6,7-tetrahydro-1-indenyl)hafnium dichloride, ethylenebis(2methyl-1-indenyl)hafnium dichloride, ethylenebis(3-methyl-1-indenyl)hafnium dichloride, ethylenebis(4-methyl-1-indenyl)hafnium dichloride, ethylenebis(5-methyl-1-indenyl)hafnium dichloride, ethylenebis(6-methyl-1-indenyl)hafnium dichloride, ethylenebis(7-methyl-1-indenyl)hafnium dichloride, ethylenebis(2,3-dimethyl-1-indenyl)hafnium dichloride, ethylenebis(4,7-dimethyl-1-indenyl)hafnium dichloride, ethylenebis(2,4,7-trimethyl-1-indenyl)hafnium dichloride, dimethysilylbis(methylcyclopentadienyl)hafnium dichloride, dimethysilylbis(t-butylcyclopentadienyl)hafnium dichloride, dimethysilylbis(dimethylcyclopentadienyl)hafnium dichloride, dimethysilylbis(trimethylcyclopentadienyl)hafnium dichloride, dimethysilyl(methylcyclopentadienyl)(dimethylcyclopentadienyl)hafnium dichloride, dimethysilylbis(methylcyclopentadienyl)(t-butylcyclopentadienyl hafnium dichloride, dimethysilylbis(1-indenyl)hafnium dichloride, dimethysilylbis (4,5,6,7-tetarhydroindenyl)hafnium dichioride, dimethysilylbis(2-methyl-1-indenyl)hafnium dichoride, dimethysilylbis(3-methyl-indenyl)hafnium dichloride, dimethysilylbis(4-methyl-1-indenyl)hafnium dichloride, dimethysilylbis(5-methyl-1-indenyl)hafnium dichloride, dimethysilylbis(6-methyl-1-indenyl)hafnium dichloride, dimethysilylbis(7-methyl-1-indenyl)hafnium dichloride, dimethysilylbis (2,3-dimethyl-1-indenyl)hafnium dichloride, dimethysilylbis(4,7-dimethyl-1-indenyl)hafnium dichloride, dimethysilylbis(2,4,7-trimethyl-1-indenyl)hafnium dichloride, dimethysilylbis(2-methyl-4-isopropyl-1-indenyl)hafnium dichloride, dimethysilylbis(4,5-benz-1-indenyl)hafnium dichloride, dimethysilylbis(2-methyl-4,5-benz-1-indenyl)hafnium dichloride, dimethysilylbis(4-phenyl-1-indenyl)hafnium dichloride, dimethysilylbis(2methyl-5-phenyl-1-indenyl)hafnium dichloride, dimethysilylbis(2-methyl-4-phenyl-1-indenyl)hafnium dichloride, dimethysilylbis(2-methyl-4-naphthyl-1indenyl)hafnium dichloride, isopropyl(3-t-butylcyclopentadienyl)(3-t-butyl-indenyl)hafnium dichloride, isopropyl(3-t-butyl-cyclopentadienyl)(3-methyl-indenyl)hafnium dichloride, and dimethyl compounds of which chlorine of these dichloride compounds above is substituted with methyl.
Furthermore, there may. be used a transition metal compound having one multidentate ligand mentioned above. Examples thereof include compounds such as dimethylsilyl(fluorenyl)(t-butylamino)zirconium dichloride, dimethylsilyl(fluorenyl)(t-butylamino)hafnium dichloride and the like.
As the aluminoxane (B) (i), there can be used those obtained by condensing one or more kinds of trialkylaluminums with water. Specific examples thereof include methylaluminoxane, ethylaluminoxane, propylaluminoxane, butylaluminoxane, isobutylaluminoxane, methylethylaluminoxane, methylbutylaluminoxane, methylisobutylaluminoxane and the like. Particularly, methylaluminoxane and methylisobutylaluminoxane are preferably used.
The amount of the aluminoxane used can be selected within the wide range as 1 to 10000 mol per 1 mol of a transition metal atom. Preferably, it is within the range from 100 to 3000 mol per 1 mol of a transition metal atom.
As the compound which reacts with the transition metal compound to form a stable anion, there can preferably be used tetrakis(pentafluorophenyl)borate- or tetarkis(pentafluorophenyl)aluminate-containing compounds, such as triphenylcarbonium tetrakis(pentafluorophenyl)borate, N,N-dimethylanilinium tetarkis(pentafluorophenyl)borate, triphenylcarbonium tetrakis(pentafluorophenyl)aluminate and the like, and tris(pentafluorophenyl)borane.
The organoaluminum compound (B) (iii) used in the present invention has at least one Alxe2x80x94C bond in the molecule, and is preferably represented by the following formula:
AlRnX3-n
(wherein R represents a hydrocarbon group having 1 to 20 carbon atoms, X represents halogen or hydrogen, and n represents a numeral satisfying the expression: 0 less than nxe2x89xa63). Specific examples of R include alkyl group having 1 to 20 (preferably 1 to 8) carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, iso-butyl, t-butyl, pentyl, hexyl, heptyl, octyl, etc.; aralkyl group having 1 to 20 (preferably up to 8) carbon atoms, such as benzyl, 4-methylbenzyl, etc.; and aryl group having 1 to 20 (preferably up to 8) carbon atoms, such as phenyl, etc. Examples of X include chlorine, bromine, iodine and hydrogen atoms. n is preferably 3.
Specific examples of the organoaluminum compound include trimethylaluminum, triethylaluminum, tripropylaluminum, tributylaluminum, tri-iso-butylaluminum, tri-t-butylaluminum, triisopropylaluminum, tripentylaluminum, trilhexylaluminum, tri(2methylpentyl)aluminum, trioctylaluminum, diethyl aluminum hydride, diisobutylaluminum hydride, methylaluminum sesquichloride, ethylaluminum sesquichloride, isobutylaluminum sesquichloride, dimethylaluminum chloride, diethylaluminum chloride, dipropylaluminum chloride, dibutylaluminum chloride, diisobutylaluminum chloride, di-t-butylaluminum chloride, diisopropylaluminum chloride, dipentylaluminum chloride, methylaluminum dichloride, ethylaluminum dichloride, isobutylaluminum dichloride, t-butylaluminum dichloride, isopropylaluminum dichloride, pentylaluminum dichloride and the like.
Among the above organoaluminum compounds, triethylaluminum and triisobutylaluminum are preferably used.
The amount of the organoaluminum compound used can normally be selected within the wide range, e.g. 1 to 10000 mol, preferably within the range from 1 to 1000 mol, per 1 mol of the transition metal atom in the transition metal compound (A).
The feedings of the respective catalyst components in a polymerization reactor, are carried out, for example, in water-free state in an inert gas (e.g. nitrogen, argon, etc.) in the presence of a monomer. The catalyst components (A) and (B) may be fed separately, or may be fed after previously contacting each other.
The polymerization temperature is usually within the range from xe2x88x9230 to 300xc2x0 C., preferably from 0 to 280xc2x0 C., more preferably from 20 to 250xc2x0 C.
The polymerization pressure is not specifically limited, but is preferably from normal pressure to about 5 atm. in view of industrial economical efficiency. The polymerization time is appropriately selected considering the kind of the desired polymer and reaction apparatus, but is usually within the range from 5 minutes to 40 hours.
A continuous or batch-wise polymerization process may be used. It is also possible to conduct slurry polymerization or solvent polymerization in an inert hydrocarbon solvent (e.g. propane, pentane, hexane, heptane, octane, etc.), bulk polymerization in a liquefied monomer (e.g. propylene, etc.), or gas phase polymerization.
It is also possible to add a chain transfer agent such as hydrogen, etc. in order to adjust the molecular weight of the propylene/ethylene-xcex1-olefin block copolymer of the present invention.
In the production of the propylene/ethylene-xcex1-olefin block copolymer of the present invention, the order of synthesizing the polypropylene component and ethylene-xcex1-olefin random copolymer component is not specifically limited, but it is preferred that propylene is polymerized in the first-stage in the presence of a catalyst, and then ethylene-xcex1-olefin random copolymerization is conducted in the second-stage in the presence of the polypropylene component formed in the first-stage.
There may be added various additives such as heat stabilizers, antioxidants, weathering stabilizers, releasants, slip agents, colorants, antistatic agents, etc. to the propylene/ethylene-xcex1-olefin block copolymer of the present invention as far as the object of the present invention is not adversely affected, in order to maintain the processing stability. There may optionally be added nucleating agents or inorganic fillers (e.g. calcium carbonate, talc, mica, silica, etc.). Furthermore, it is also possible to blend the propylene/ethylene-xcex1-olefin block copolymer of the present invention with a resin such as an olefin resin (e.g. another propylene polymer, an ethylene polymer, polybutene, etc.), an acrylonitrile-butadiene-styrene copolymer resin or a rubber such as a styrene rubber (e.g. styrene/ethylene-butene/styrene block copolymer, etc.).
The propylene/ethylene-xcex1-olefin block copolymer of the present invention can be molded into various molded articles such as sheet, film, bottle, etc. by adding additives described above, optionally blending fillers and various resins or rubbers, melt-kneading using an extruder, a Banbury mixer, a kneader blender, etc. to form pellets, followed by molding according to an injection molding, extrusion molding or blow molding. The propylene/ethylene-xcex1-olefin block copolymer of the present invention can be used for various purposes because of excellent mechanical characteristics such as impact resistance, etc. For example, it is possible to be use for purposes such as part for electrical apparatus, automobile interior/exterior part, vessel for detergent and the like. Further, there may be used the propylene/ethylene-xcex1-olefin block copolymer especially having a polypropylene component content of not less than 5% by weight and less than 50% by weight of the present invention as a modifier for improving an impact strength of a polyolefin resin such as a polypropylene by adding to the polyolefin resin.
The following Examples further illustrate the present invention in detail but are not to be construed to limit the scope thereof.
Measured values of the respective items in the Examples were determined by the following methods.
(1) Stereoregularity
It was determined by the 13C-nuclear magnetic resonance spectrum method. 13C-NMR of the polymer was determined by measuring a solution, prepared by dissolving about 150 mg of the polymer in 3 ml of ortho-dichlorobenzene, in a test tube of 10 mmxcfx86 under the conditions of a measuring temperature of 135xc2x0 C., a measuring frequency of 67.8 MHz, a spectral width of 3000 Hz, a filter width of 100000 Hz, a pulse repeating time of 10 seconds, a pulse width of 45xc2x0 and an integrating times of 5000 to 7000.
(2) Content of Ethylene-xcex1-olefin Random Copolymer and xcex1-olefin Content and xcfx81 Value
{circumflex over (1)} Quantitative determination of content of ethylene-1-butene random copolymer component, ethylene-1-hexene random copolymer component and ethylene-1-octene random copolymer component, and xcex1-olefin content
They were determined by the 13C-nuclear magnetic resonance spectrum method described in James. C. Randall, Sci., Macromol. Chem. Phys., C29 (2xcex53), 29,201-317 (1989).
The measurement of 13C-NMR of the polymer was conducted according to the same manner as that described in the above item (1).
{circumflex over (2)} Content of ethylene-propylene random copolymer component
The quantitative determination (% by weight) of the ethylene-propylene copolymer component was conducted by measuring each heat of fusion a whole propylene/ethylene-propylene block copolymer and a polypropylene component, followed by calculating using the following equation.
The crystal melting heat quantity was determined by previously melting 10 mg of a sample under a nitrogen atmosphere at 220xc2x0 C. for 5 minutes using a differential scanning calorimeter (manufactured by Perkin Elmer Co., DSC), cooling to 50xc2x0 C. at a cooling rate of 130xc2x0 C./minute to crystallize the molten sample, heating to 180xc2x0 C. at a heating rate of 16xc2x0 C./minute, and calculating from the resulting melting-endothermic curve.
X={1xe2x88x92(xcex94Hf)T/(xcex94Hf)P}xc3x97100
wherein X is a content (% by weight) of an ethylene-propylene random copolymer component, (xcex94Hf)T is a melting heat quantity (cal/g) of a whole propylene/ethylene-propylene block copolymer and (xcex94Hf)P} is a melting heat quantity (cal/g) of a polypropylene component.
{circumflex over (3)} xcfx81 value of ethylene-xcex1-olefin random copolymer component
It was determined by calculating from a molar fraction ([E]) of ethylene in an ethylene-xcex1-olefin random copolymer component, a molar fraction ([A]) of an xcex1-olefin and a molar fraction ([EA]) of a diad chain of ethylene and an xcex1-olefin, determined by the 13C-nuclear magnetic resonance spectrum method described in James. C. Randall, Macromol. Chem. Phys., C29 (2xcex53), 29, 201-317 (1989), according to the following general formula:
xcfx81=2[E]xc2x7[A]/[E]
(3) Weight Average Molecular Weight (Mw), and Weight Average Molecular Weight/number Average Molecular Weight (MW/Mn)
The Mw was measured by gel permeation chromatography (GPC) under the following conditions. A calibration curve was made by using standard polystyrene.
Model: 150CV, manufactured by Millipore Water Co.
Column: Shodex M/S 80
Measuring temperature: 145xc2x0 C., solvent: orthodichlorobenzene
Sample concentration: 5 mg/8 ml
Incidentally, Standard Reference Material 706 (polystyrene having Mw/Mn of 23.1) of NSB (National Bureau of Standard) was measured under above-described conditions. As a result, a molecular weight distribution (Mw/Mn) of 2.1 was obtained.
(4) Intrinsic Viscosity ([xcex7]: dl/g)
It was measured in tetralin at 135xc2x0 C.
(5) Melting Point (Tm: xc2x0 C.)
It was determined by previously melting 10 mg of a sample under a nitrogen atmosphere at 220xc2x0 C. for 5 minutes using a differential scanning calorimeter (manufactured by Perkin Elmer Co., DSC), cooling to 50xc2x0 C. at a cooling rate of 5xc2x0 C./minute to crystallize the molten sample, heating at a heating rate of 10/minute, and determining a temperature of a maximum peak of the resulting melting-endothermic curve as the melting point.
(6) Density (g/cm3)
The press molding and conditioning are conducted according to JIS K6758. The measurement was conducted after a lapse of 48 hours at 23xc2x0 C. since molding. The measurement is conducted according to JIS K7112.
(7) Flexural Modulus (Kg/cm2)
The press molding and conditioning are conducted according to JIS K6758. The measurement was conducted after a lapse of 48 hours at 23xc2x0 C. since molding. The measurement is conducted according to JIS K7203.
(8) Izod Impact (Kgxc2x7cm/cm2)
The press molding and conditioning are conducted according to JIS K6758. The measurement was conducted after a lapse of 48 hours at 23xc2x0 C. since molding. In the measuring at a temperature of xe2x88x9220xc2x0 C., the measurement was conducted after an additional lapse of 2 hours at xe2x88x9220xc2x0 C. A sample with a V-shaped notch was measured by using an Izod impact tester (manufactured by Toyo Seiki Co., Ltd.) (JIS K7110).
(9) Melt Index (MI: g/10 minute)
It was measured with a melt indexer manufactured by Techno Seven Co., Ltd. under the conditions of a load of 2.16 kgf and a specific measuring temperature (a polypropylene resin: 230xc2x0 C., an ethylene-xcex1-olefin random copolymer: 190xc2x0 C.) (JIS K7210).
As the transition metal compound (A) having a cyclopentadienyl ring of Group IV of the Periodic Table, the compound (B) (ii) which reacts with the transition metal to form a stable anion, and (B) (iii), the followings were used.
(A) Transition Metal Compound
As dimethylsilylbis(1-indenyl)hafnium dichloride, a commercially available product manufactured by Nippon Fine Chemical Co., Ltd. was used.
(B) (ii) Compound Which Reacts with the Transition Metal to form a Stable Anion
A commercially available product manufactured by Toso Akzo Co., Ltd., triphenylcarboniumtetrakis(pentafluorophenyl)borate was used.
(B) (iii) Organoaluminum Compound
A commercially available product manufactured by Toso Akzo Co., Ltd., triisobutylaluminum was used.